Not Updated For Current Season
As you all know Nocturne is the newest champion to join the league, he is a shadowy figure who is extremely good at ganking but has not got 'great' survivability in group fight, so this means you should really just jump in and out of fight picking of those people who over-extend of decide to try and back door you, he is excellent as stopping people back door you because of his ulti, you can use it on that person and jump from one lane to another because of its enormous range, His ulti also matches up with Twisted Fates ulti extremely well as nocturnes ulti doesn't actually reveal the champion for you, meaning TF can reveal the enemy champions for you so it is easier for you to gank.
Before Nocturne, people believed that dreams were figments of their imagination, meaningless images that flashed through the mind when one slept. This belief was put to the test when a rash of sleep-related incidents started afflicting summoners of the League. Some would wake up screaming, terrified and beyond consolation. Some could not fall asleep, slowly going mad as the nights ticked by. Some simply never woke up. Physicians were baffled until a Field Architect happened to pass out next to a nexus on Twisted Treeline. Witnesses said he cried out once and then stopped breathing. Immediately after, magical energy arced out from the nexus, and Nocturne appeared.
Nocturne did not take his introduction to this world kindly. He slaughtered everything he could find before summoners were able to magically confine him. After a period of intense study, League experts divined that Nocturne hunted summoners in their sleep, attacking them in a place where their magic was useless. This seemed to be his only purpose. The families of the victims demanded justice, but League officials were concerned that death might only return Nocturne to the place from which he came. They bound him to a nexus fragment, trapping him in the physical world. As punishment for his crimes, they allowed summoners to call upon Nocturne in the League matches, bending his will to the summoners he hates and creating his own personal nightmare. League scholars don't know whether he truly came from the plane of dreams, or whether there are any more like him. Some theorize that the summoning act affected summoners' subconscious minds, luring Nocturne to them in their sleep. Perhaps the most disturbing theory is that Nocturne is a person's nightmare come to life. If this is true, they wonder, who is the dreamer?
''The darkness is closing in...it's pitch black now...but I can still see him...''
- Kelvin Ma, patient #4236
Duskbringer - Nocturne throws a shadow blade which deals damage, leaves a Dusk Trail, and causes champions to leave a Dusk Trail. While on the trail, Nocturne ignores unit collision and has increased Movement Speed and Attack Damage.
Nocturne throws a shadow blade which deals 60/110/160/210/260 (+) physical damage and leaves a Dusk Trail for 5/5/5/5/5 seconds. Enemy champions hit also leave a Dusk Trail.
While on the trail, Nocturne ignores unit collision and gains 15/20/25/30/35% Movement Speed and 20/30/40/50/60 Attack Damage.
Shroud of Darkness - Nocturne empowers his blades, passively gaining attack speed. Activating Shroud of Darkness allows Nocturne fades into the shadows, creating a magical barrier which blocks a single enemy spell and doubles his passive attack speed if successful.
Passive: Nocturne has 20/25/30/35/40% bonus Attack Speed.
Active: Nocturne creates a magical barrier for 2 seconds, which blocks the next enemy ability.
If an ability is blocked by the shield, Nocturne's passive Attack Speed bonus doubles for 5 seconds.
Unspeakable Horror - Nocturne plants a nightmare into his target's mind, dealing damage each second and fearing the target if they do not get out of range by the end of the duration.
Nocturne plants a nightmare into his target's mind, dealing 50/100/150/200/250 (+1) magic damage over 2 seconds. If Nocturne stays within 600 range of the target for the full duration, the target becomes feared for 1/1.25/1.5/1.75/2 second(s).
Paranoia - Nocturne reduces the sight radius of all enemy champions and removes their ally vision in the process. He can then launch himself at a nearby enemy champion.
Nocturne reduces the sight radius of all enemy champions and removes their ally vision for 4 seconds.
While Paranoia is active, Nocturne can launch himself at an enemy champion, dealing 150/300/450 (+) physical damage.
Umbra Blades - Every 10 seconds, Nocturne's next attack strikes surrounding enemies for 120% physical damage and heals himself for 15/20/25 per target hit.
Nocturne's basic attacks reduce this cooldown by 1 second.
Early game you should grab a dorans blade and go into a lane (due to his passive you shouldn't really need any health pots while in a lane), or if you are jungling grab cloth armor and 3-5 health pots (depending how skilled you are). at about level 6, or when you go back to get health if you need to, you should grab beserker's boots, or mercury treads if the over team have lots of stuns, snare etc. or if you are jungling get your madred's razors first then your boots.
by mid game you should be going up and down between lanes getting ganks of where possible and using your ulti to get between lanes faster. If you are having no problem surviving i recommend going straight for phantom's dancer as the attack speed it gives is really useful for nocturne as he is an AD character, but if you are having problems surviving get a bit of lifesteal (vampiric scepter. By about level 11 you should have at least your phantom's dancer and getting your first bloodthirster
Item building late game you really have two ways to go. One way is that if the opposite team is heavy and tanks then get a madred's bloodrazor as once you get this you should have around 2 attacks per second meaning you do 8% of the person health in one second, which comes in really handy if you are versing tanky people. On the other hand though if you are versing quite squishy people you may want to skip the madred's bloodrazor and get something like a black clever or another bloodthirster (although 2 should be more than enough to keep you alive as you should really only jump in and out of fights) this is because if you are versing squishy people the madred's 4% each hit will not be doing 'extremely' much damage meaning you are better of just building more AD, If you are having problem with people getting away from you (although you shouldn't because of you Duskbringer and your fear), you may consider getting a Frozen Mallet, the 700 health also comes in handy if you are having problems surviving.
By the time you are fully fed you should have just over 50% crit chance and be critting over 1k damage, and also have above 2 APS (without the double passive effect off your Shroud of Darkness) meaning you should be able to easy gank anyone, just about, and kill them within a few seconds (usually before you ulti gets off if you use it to engage)
Nocturne is really easy to Farm on due to hit passive and therefore you should really be on the higher end of minion kills rather than the lower end. This also gives a boost late game because you should really be getting above 100 minions kills each game (unless it is a really short game) and nocturne is pretty easy to get fed on, ATM, meaning you should really be also having quite a few champion kills as well.
Im still working on clips for the video of him, once i have them and make the vid ill put it up for you'ze to see. xD
Also I'll be adding a jungling guide addition onto this guide aswel (as you may have noticed i have already put bits on it in the guide), im still working on the route and stuff so shouldn't be much longer